Soy Protein May Reverse Atherosclerotic Progression

WINSTON-SALEM, N.C.--Long-term supplementation with soy protein appears to reduce the size of atherosclerotic plaques without affecting reactivity of the coronary artery (J Nutr, 135:2852-6, 2005). Researchers from the Wake Forest University School of Medicine conducted a 31-month study in adult male monkeys to determine the impact of atherogenic diets with different protein sources. The diets included a low-isoflavone soy protein isolate (0.94 mg isoflavones/g protein) diet, a high-isoflavone soy protein isolate (1.88 mg isoflavone/g protein) diet, and a control (casein/lactalbumin) diet.

Compared with control, both soy protein groups showed reductions in plasma low-density lipoprotein (LDL) cholesterol and increases in high-density lipoprotein (HDL) cholesterol and apolipoprotein A-1. In addition, both soy protein groups showed a reduction of approximately 34 percent in atherosclerosis, as judged by mean plaque size in the coronary arteries. The soy diet did not impact endothelium-dependent or -independent arterial reactivity.